The present invention relates to a battery pack comprising heat-diffusing means from a plurality of battery cells located in a housing.
Rechargeable battery packs are used for operating power tools, for instance. Both during the operation of a battery pack, or in other words during its discharging process, and in the charging process, the currents flowing through the battery cells cause severe heating up of the battery cells. So that in the charging process the temperature of the battery cells will not exceed a maximum allowable threshold—which would lead to destruction of the battery cells—the charging current must be reduced, with the consequence that the charging time for the battery pack is lengthened. If a higher charging current and accordingly a shorter charging time for the battery pack are to be attained, excessive heating of the battery pack must be avoided. In the prior art, measures are therefore taken to diffuse heat of the battery cells from the battery pack. For instance, in European Patent Disclosure EP 940 864 B1 , a ventilation system for the battery pack is provided for this purpose; it allows air to flow through the interior of the housing of the battery pack. To that end, air inlet and air outlet openings are provided in the battery pack housing. A disadvantage is that with the flow of air through the housing of the battery pack, dirt particles can also get into the interior of the battery pack. Soiling in the interior of the battery pack, however, can change heat transfers among battery cells and can also impair the electrical function of the battery pack. The parts located in the interior of the battery pack form a high air resistance, which impairs the effectiveness of the heat diffusion.